The differential communication circuit is a circuit that is configured to switch the transmission signal to a HIGH state or to a LOW state based on a potential difference between a pair of signal lines that serve as bus lines. In such a differential communication circuit, a high impedance caused by a bus switching from a drive state to a non-drive state generates a ringing, and an otherwise zero potential difference may be falsely detected as exceeding a signal level threshold, and may lead to an unstable signal level determination.
As disclosed in a patent document 1 listed below, a device uses a bus to drive a first and second switch by applying a forward voltage during an ON period, and drives a third and fourth switch using a reverse voltage during an OFF period of the first and second switches. In such manner, when the first/second switches turn from ON to OFF, the bus has a negative potential difference, thereby preventing an over-threshold signal level even when ringing is caused, and enabling a stable signal level determination.
(Patent Document 1) U.S. Pat. No. 9,223,736
The device in patent document 1 supplies a drive current to the bus during the entire OFF period of the first/second switches by turning the third/fourth switches to ON, which causes an increase in power consumption.
While differential circuits are suitable for their intended use, they are subject to improvement. For example, current differential circuits may consume unnecessary power during their use. The present teachings provide embodiments of differential circuits that address such shortcomings in the art and provide numerous advantages as well.